Peritoneal dialysis is a recognized treatment for end-stage renal failure in which dialysis fluid is introduced from a sterile source into the peritoneal cavity of a patient suffering end-stage renal failure. The dialysis fluid exchanges metabolites from the patients blood through the peritoneal membrane. The dialysis fluid containing metabolites is then removed from the peritoneal cavity.
Peritoneal dialysis is distinguishable from hemodialysis in which direct cleansing of the patient's blood is performed outside of the body by means of synthetic membranes in an artificial kidney machine having fluid connection with the patient's blood stream. Hemodialysis has three major disadvantages: the need (a) for large quantities of dialysis fluid, (b) the requirement that the dialysis fluid be isotonic to the blood so as to prevent electrolyte content of the blood from being diminished, and (c) the limitation to intermittent operation of the blood cleansing cycle due to the necessity of fluid connection of the patient to an artificial kidney machine for long periods of time. Such intermittent operation results in the maintenance of periodically high and then low concentrations of the toxic metabolities in a patient's blood, with corresponding adverse side effects.
With the use of peritoneal dialysis, cleansing or metabolite exchange of the blood with dialysis fluid occurs for the full period of time that dialysis fluid resides in the peritoneal cavity. Such exchange time is limited only by the requirement to drain the dialysis fluid from the peritoneal cavity, when such fluid has reached equilibrium with the blood, and to provide fresh fluid to the peritoneal cavity. Therefore, such dialysis systems have come to be termed continuous peritoneal dialysis as distinguished from intermittent dialysis, such as hemodialysis.
Continuous peritoneal dialysis is performed either on a truly continuous basis, as described in U.S. Pat. No. 3,825,493 to Brown et al., by circulating dialysis fluid through the peritoneal cavity and subsequently a filtration and makeup apparatus, or by periodic removal of infused dialysis fluid from the peritoneal cavity and replacement with fresh dialysis fluid, as described by D. G. Oreopoulos et al., Vol. XXIV Trans. Am. Soc. Artif. intern. Organs 1978. The latter system is only limited by the time required to drain the peritoneal cavity and to provide fresh dialysis fluid to said cavity.
The dialysis system described by Brown et al. suffers from the disadvantages of requiring two catheter connections to the peritoneal cavity for circuitous fluid flow, the bulk and expense of providing a complete ambulatory filtration and makeup apparatus to be worn by the patient and the requirement of high speed pumping of the peritoneal fluid.
In U.S. Pat. No. 3,799,873 to Brown, a peritoneal dialysis apparatus is described with a circuitous fluid flow path between the peritoneal cavity and a dialysing apparatus similar to Brown et al., above. Brown requires the circulation of the peritoneal fluid continuously with a complex, bulky and expensive exchange, filtration and makeup apparatus or a double fluid circuit system. The disadvantages of such an apparatus, designed for ambulatory use, but requiring several fluid reservoirs, a power source and a pumping means, are obvious.
D. G. Oreopoulos, M. Robson, S. Izatt, S. Clayton, and G. A. deVeber; A simple and Safe Technique for Continuous Ambulatory Peritoneal Dialysis (CAPD), Vol. XXIV Transactions of American Society of Artifical Internal Organs (1978) p. 484 and J. W. Moncrief, K. D. Ralph, J. Rubin and R. P. Popovich; Additional Experience with Continuous Ambulatory Peritoneal Dialysis (CAPD), Vol. XXIV Transactions of American Society of Aftificial Internal Organs (1978) p. 476 describe a peritoneal dialysis system which utilizes individual bags of fresh dialysis fluid which are infused into the peritoneal cavity of a patient by means of a simple flow line. The fluid is allowed to equilibrate with the blood across the peritoneal membrane, and, when equilibrium is achieved, the fluid is returned to the bag. The bag is then disconnected from the patient's peritoneal catheter. A fresh bag of dialysis fluid is needed for the next infusion. Five infusions per day for six days a week are prescribed. This system suffers from the disadvantages of the large amount of fresh dialysis fluid required, the need for numerous sterile dialysis bags, and, most important, the requirement for frequent sterile connections and disconnections of the dialysis bag to the peritoneal catheter. The latter requirement creates opportunities for infection and the development of peritonitis. Peritonitis can preclude the use of peritoneal dialysis during the duration of such an infection, or, at the minimum, require additional treatment of the patient with antibiotics.
All of the systems described above have the additional disadvantage of protein loss in the dialysis process. The peritoneal fluid infused in the body absorbs proteins from the body. This protein is lost from the body when the fluid is removed permanently from the body or when the protein containing fluid is filtered and recirculated. Proteins do not normally pass through the filtration or exchange membranes of fine structure such as used in such dialysis systems.
Other prior art references concerned with dialysis, but not highly relevant to this subject include U.S. Pat. Nos. 3,518,982; 3,864,259, 3,884,808 and 3,962,094.